Technical Field
The present invention relates to reaction vessels, and in particular to a coal gasification vessel.
Gasification of coal to produce methane gas could provide a much needed replacement or supplement for dwindling supplies of natural gas. Unfortunately, the conversion of coal to gas occurs most economically at extremely severe conditions. These include a temperature of around 2500.degree. F. (1370.degree. C.), a pressure of about 1500 psi (100 atms) and in a very corrosive and abrasive atmosphere.
A projected typical size and shape for a conversion vessel is a cylinder approximately 30 feet (9.1 m) in diameter and 150 feet (45.7 m) long. To withstand the pressures required, the cylinder would be approximately 14 inches (35.5 cm) thick if the vessel were made of steel. Obviously, such a structure would be very heavy, very expensive and difficult to build, principally due to the difficulty in welding steel sections of such thickness and checking such welds for flaws. Such a structure would most probably be built on the site, since, due to its great size and weight, it would be quite difficult to move same.
It is known to use carbon fiber or graphite fiber in combination with resins used as binders to construct structures such as missile launching tubes. Such structures are many times lighter and easier to construct than similar structures comprised of steel and the like.
The conversion vessel would further include an interior shell of refractory material, such as refractory concrete, which would protect the steel vessel from the extreme heat of gasification reaction. Since the refractory material would gradually break down, with the development of a hot spot, the wall temperature must be monitored almost continually so that the refractory material can be replaced before the steel wall of the vessel is damaged. Monitoring by detecting infrared emission or by other methods from the outside of the vessel would be extremely difficult, since the auxiliary equipment necessarily surrounding the vessel would make access difficult. Further, the use of thermocouples and other point measuring devices would most likely not be satisfactory for monitoring temperature over an extended area, even if they could survive the hostile environment within the vessel.
It should also be noted that, along with monitoring the wall temperature, there may need to be provisions for cooling the wall or otherwise protecting the wall from the heat of the reaction. Cooling coils have been used in some vessel designs to provide coolant to protect the vessel wall.
It is an object of the present invention to provide a vessel for use in a high temperature, high pressure and corrosive environment which is found during the gasification of coal.
Another object of the present invention is to provide such a vessel which is relatively lightweight and easy to construct in comparison to the present state of the art.
Still another object of the present invention is to provide apparatus for the vessel which can not only cool the vessel but can monitor and locate high temperature spots which could be caused by, for example, a disintegration in the refractory material.
Still another object of the invention is to provide for safe operation of the vessel even though the refractory material thereof has disintegrated, until such time as it is safe to shut down the reaction in order to repair the refractory material.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or will be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.